Acoustic imaging agent

Abstract

An imaging agent, a method of production of the imaging agent, and the use of the imaging agent for microseismic monitoring of subterranean formations such as those generated during hydraulic fracturing. The acoustic emitting agent is tailorable for emission delay to ensure placement and frequency emission profiles for well region differentiation. This monitoring tool is highly useful in gas, oil, and geothermal well defining and stimulation monitoring.

What is claimed is: 
     
       1. An acoustic imaging agent that can be used to map subterranean formations; said acoustic imaging agent comprised of a plurality of base particles mixed with a matrix material; each of said plurality of said base particles has a crush strength and configured to fracture or crush when pressure about said base particle exceeds said crush strength of said base particle; said crush strength of each of said base particle is 10-20,000% less than a crush strength of said acoustic imaging agent; said plurality of base particles are hollow spheres; said hollow spheres include one or more materials selected from the group consisting of water glass, glass and ceramic; said hollow spheres having a diameter of 10 μm to 1 mm; said hollow spheres having a wall thickness of 0.1 μm to 200 mm; said hollow spheres having a crush strength of 100-19000 psi; said matrix material formed of over 50 wt. % of one or more materials selected from the group consisting of polymer and metal; each of said plurality of base particles is configured to produce an acoustic signal or emission when crushed or fracture such that at least one peak frequency of said acoustic signal or emission is about 0.4 Hz to below 10,000 Hz; a diameter of said acoustic imaging agent is up to 10 mm; and
 wherein the produced acoustic signals or emissions from said crushed or fractured base particles can be used to locate said acoustic imaging agent in the subterranean formation. 
 
     
     
       2. The acoustic imaging agent as defined in  claim 1 , wherein said matrix material includes one or more additives selected from the group consisting of a) reinforcing agent to increase said crush strength of said acoustic imaging agent, b) degrading agent to increase a degradation rate of said outer coating or matrix material, and c) dense particle additive to increase a density of said acoustic imaging agent; said one or more additives constitute 0.001-30 wt. % of said matrix material; said one or more additives having a size of about 10 nm-1 mm. 
     
     
       3. The acoustic imaging agent as defined in  claim 2 , wherein a) said dense particle additive has a density of at least 1.7 g/cc and constitutes about 0.001-30 wt. % of said matrix material; said dense particle additive is added in sufficient quantities to said matrix material to increase a density of said acoustic imaging agent by 0.5-5 g/cc, b) said reinforcing agent constitutes about 0.001-10 wt. % of said matrix material; said reinforcing agent increasing said crush strength of said acoustic imaging agent by 10% to 2000%, and c) said degrading agent constitutes about 0.001-10 wt. % of said matrix material; said degrading agent reducing a time of degradation of said matrix material by at least 5%. 
     
     
       4. The acoustic imaging agent as defined in  claim 1 , wherein a pressure in said plurality of hollow spheres is about 10-19,000 psi. 
     
     
       5. The acoustic imaging agent as defined in  claim 1 , wherein said matrix material includes one or more materials selected from the group consisting of polyvinylalcohols, polycarbohydrates, polycarbonates, polylactic acid, polyglycholic acid, poly(lactic-co-glycolic acid), polyamine, and polyester. 
     
     
       6. The acoustic imaging agent as defined in  claim 1 , wherein said matrix material includes one or more materials selected from the group consisting of magnesium, calcium, and magnesium-nickel alloy. 
     
     
       7. The acoustic imaging agent as defined in  claim 1 , wherein said plurality of said base particles constitute about 0.01-60 vol. % of said acoustic imaging agent. 
     
     
       8. The acoustic imaging agent as defined in  claim 1 , wherein said acoustic imaging agent has a crush strength of at least 1,000 psi. 
     
     
       9. The acoustic imaging agent as defined in  claim 1 , said plurality of base particles include first and second base particles; and wherein I) said first base particle has a pressure in said hollow sphere that is different from a pressure in said hollow sphere of said second base particle such that said first base particle generates a different peak frequency from said second base particle when said first and second base particles are fractured or crushed, II) said wall thickness of said first base particle is different from said wall thickness of said second base particle such that said first base particle generates a different peak frequency from said second base particle when said first and second base particles are fractured or crushed, III) said first base particle has a composition that is different from a composition of said second base particle such that said first base particle generates a different peak frequency from said second base particle when said first and second base particles are fractured or crushed, and/or IV) said first base particle has a diameter that is different from a diameter of said second base particle such that said first base particle generates a different peak frequency from said second base particle when said first and second base particles are fractured or crushed. 
     
     
       10. An acoustic imaging agent that can be used to map subterranean formations; said acoustic imaging agent comprised of a base particle and a coating material; said base particle has a crush strength and configured to fracture or crush when pressure about said base particle exceeds said crush strength of said base particle; said crush strength of said base particle is 10-20,000% less than a crush strength of said acoustic imaging agent; said base particle is a hollow sphere; said hollow sphere includes one or more materials selected from the group consisting of water glass, glass and ceramic; said hollow sphere has a diameter of 10 μm to 1 mm; said hollow sphere has a wall thickness of 0.1 μm to 200 mm; said coating material has a coating thickness of 10 nm to 1,000 μm; said hollow sphere has a crush strength of 100-19000 psi; said coating material is formed of over 50 wt. % of one or more materials selected from the group consisting of polymer and metal; said base particle is configured to produce an acoustic signal or emission when crushed or fracture such that at least one peak frequency of said acoustic signal or emission is about 0.4 Hz to below 10,000 Hz; a diameter of said acoustic imaging agent is up to 10 mm; and
 wherein the produced acoustic signal or emission from said crushed or fractured base particle can be used to locate said acoustic imaging agent in the subterranean formation. 
 
     
     
       11. The acoustic imaging agent as defined in  claim 10 , wherein said acoustic imaging agent has a crush strength of at least 1,000 psi. 
     
     
       12. The acoustic imaging agent as defined in  claim 10 , wherein said coating material includes one or more materials selected from the group consisting of polyvinylalcohols, polycarbohydrates, polycarbonates, polylactic acid, polyglycholic acid, poly(lactic-co-glycolic acid), polyamine, and polyester. 
     
     
       13. The acoustic imaging agent as defined in  claim 10 , wherein said coating material includes one or more materials selected from the group consisting of magnesium, calcium, and magnesium-nickel alloy. 
     
     
       14. The acoustic imaging agent as defined in  claim 10 , wherein said coating material includes one or more additives selected from the group consisting of a) reinforcing agent to increase said crush strength of said acoustic imaging agent, b) degrading agent to increase a degradation rate of said outer coating, and c) dense particle additive to increase a density of said acoustic imaging agent; said one or more additives constitute 0.001-30 wt. % of said matrix material; said one or more additives having a size of about 10 nm-1 mm. 
     
     
       15. The acoustic imaging agent as defined in  claim 14 , wherein a) said dense particle additive has a density of at least 1.7 g/cc and constitutes about 0.001-30 wt. % of said coating material; said dense particle additive is added in sufficient quantities to said coating material to increase a density of said acoustic imaging agent by 0.5-5 g/cc, b) said reinforcing agent constitutes about 0.001-10 wt. % of said coating material; said reinforcing agent increasing said crush strength of said acoustic imaging agent by 10% to 2000%, and c) said degrading agent constitutes about 0.001-10 wt. % of said coating material; said degrading agent reducing a time of degradation of said coating material by at least 5%. 
     
     
       16. A plurality of acoustic imaging agent that can be used to map subterranean formations; each of said acoustic imaging agent comprises a base particle and a coating material; said base particle in each of said acoustic imaging agent has a crush strength and configured to fracture or crush when pressure about said base particle exceeds said crush strength of said base particle; said crush strength of said base particle in each of said acoustic imaging agent is 10-20,000% less than a crush strength of said acoustic imaging agent; said base particle in each of said acoustic imaging agent is a hollow sphere; said hollow sphere of said base particle in each of said acoustic imaging agent includes one or more materials selected from the group consisting of water glass, glass and ceramic; said hollow sphere of said base particle in each of said acoustic imaging agent has a diameter of 10 μm to 1 mm; said hollow sphere of said base particle in each of said acoustic imaging agent has a wall thickness of 0.1 μm to 200 mm; said coating material of each of said acoustic imaging agent has a coating thickness of 10 nm to 1,000 μm; said hollow sphere of said base particle in each of said acoustic imaging agent has a crush strength of 100-19000 psi; said coating material of each of said acoustic imaging agent is formed of over 50 wt. % of one or more materials selected from the group consisting of polymer and metal; said base particle of each of said acoustic imaging agent is configured to produce an acoustic signal or emission when crushed or fracture such that at least one peak frequency of said acoustic signal or emission is about 0.4 Hz to below 10,000 Hz; a diameter of each of said acoustic imaging agent is up to 10 mm; and wherein the produced acoustic signal or emission from said crushed or fractured base particle in each of said acoustic imaging agent can be used to locate said acoustic imaging agent in the subterranean formation. 
     
     
       17. The plurality of acoustic imaging agent as defined in  claim 16 , wherein said plurality of said acoustic imaging agent includes I) one or more of said acoustic imaging agents having a pressure in said hollow cavity that is different from one or more other of said acoustic imaging agents such that said acoustic imaging agents generate different peak frequencies of said acoustic signal or emission when crushed or fractured, II) one or more of said acoustic imaging agents having a base particle with a wall thickness that is different from one or more other of said acoustic imaging agents such that said acoustic imaging agents generate different peak frequencies of said acoustic signal or emission when crushed or fractured, III) one or more of said acoustic imaging agents having a base particle composition that is different from one or more other of said acoustic imaging agents such that said acoustic imaging agents generate different peak frequencies of said acoustic signal or emission when crushed or fractured, and/or IV) one or more of said acoustic imaging agents having a base particle size that is different from one or more other of said acoustic imaging agents such that said acoustic imaging agents generate different peak frequencies of said acoustic signal or emission when crushed or fractured. 
     
     
       18. The plurality of acoustic imaging agent as defined in  claim 16 , wherein each of said acoustic imaging agent has a crush strength of at least 1,000 psi. 
     
     
       19. The plurality of acoustic imaging agent as defined in  claim 16 , wherein said coating material on two or more of said acoustic imaging agent includes one or more materials selected from the group consisting of polyvinylalcohols, polycarbohydrates, polycarbonates, polylactic acid, polyglycholic acid, poly(lactic-co-glycolic acid), polyamine, and polyester. 
     
     
       20. The plurality of acoustic imaging agent as defined in  claim 16 , wherein said coating material on two or more of said acoustic imaging agent includes one or more materials selected from the group consisting of magnesium, calcium, and magnesium-nickel alloy. 
     
     
       21. The plurality of acoustic imaging agent as defined in  claim 16 , wherein two or more of said acoustic imaging agents include one or more additives selected from the group consisting of a) reinforcing agent to increase said crush strength of said acoustic imaging agent, b) degrading agent to increase a degradation rate of said outer coating material, and c) dense particle additive to increase a density of said acoustic imaging agent; said one or more additives constitute 0.001-30 wt. % of said coating material; said one or more additives having a size of about 10 nm-1 mm. 
     
     
       22. The acoustic imaging agent as defined in  claim 21 , wherein a) said dense particle additive has a density of at least 1.7 g/cc and constitutes about 0.001-30 wt. % of said coating material; said dense particle additive is added in sufficient quantities to said coating material to increase a density of said acoustic imaging agent by 0.5-5 g/cc, b) said reinforcing agent constitutes about 0.001-10 wt. % of said coating material; said reinforcing agent increasing said crush strength of said acoustic imaging agent by 10% to 2000%, and c) said degrading agent constitutes about 0.001-10 wt. % of said coating material; said degrading agent reducing a time of degradation of said coating material by at least 5%.